SNMP

SNMP stands for 'Simple Network Management Protocol'. It belongs to the TCP/IP protocol family and enables the management of devices in an IP network, such as routers, switches, workstations etc. There are several variants which are defined in the corresponding RFCs:

• SNMP V1
• SNMP V2
• SNMP V3

SNMP distinguishes between an agent (server) which supplies the data and a manager (client) which accesses the data.

Data transmission is based on the connectionless UDP protocol.

The data is encoded as per ASN.1 (ISO/IEC 8824), Basic Encoding Rules (BER).

OIDs or object identifiers are used for data addressing. An OID has a hierarchical structure consisting of a string of decimal numbers separated by a point '.', for instance  .1.3.6.1.2.1. Each number is assigned a symbol depending on the level to make it more readable, for instance .iso.org.dod.internet.mgmt.mib-2. The meaning of the numbers on each level is defined and also reveals the meaning of the object addressed this way.
The address space consists of a standardized and a proprietary part. In the standardized part, standardized information objects are defined (for instance MIB II), while the proprietary area is reserved for manufacturer-specific objects (.1.3.6.1.4.1 [.iso.org.dod.internet.private.enterprises]). Many manufacturers use their proprietary identifiers for managing device-specific information. MIB files encoded in ASN.1 format allow the definition of the information (Management Information Block).